Electrode structure



A. H. STAIGER ELECTRODE STRUCTURE Filed Oct. 25. 1929 R R 0+0- N TE v Ym R N E H p E R F L A A'ITORNEY Patented Oct. 13, 1931 UNITED STATES.

ALFRED HENRY STAIGER, OF NEW YORK, N. Y.

. ELECTRODE STRUCTURE I Application filed October 25, 1929. Serial 1E0. 402,374.

This invention relates to electrical discharge devices, particularly to illuminating tubes.

It is an object of my invention to construct .5 an improved form of electrode structure which will insure longer life and more uniform operation of an electrical discharge device.

Other objects and advantages will be made clear in the following description and accompanying drawings.

In the drawings, Fig. 1 illustrates in vertical cross-section an electrode structure constructed in accordance with my invention;

and

Fig. 2 shows the electrode of Fig. 1 as incorporated in a complete tube.

Referring more particularly to the drawings, reference numeral 1 indicates an envelope of glass or other transparent material having positioned therein a block or body of insulating material 2 which may be, for example, of Lavite, or other material of that general'nature, which is able to withstand 2 heat. The upper end of the block 2 has a rim portion 3 which extends upwardly, thereby forming an opening 4: into which projects a rod of conducting material 5, preferably of tantalum. This rod passes through a perforation 6 in the insulating material and is threaded to receive nuts 7 and 8. The nut 7 ma be of insulating material so that all of the discharge which takes place will be directly to the rod 5. A lead-in wire 9 is connected to the end of rod 5 and sealed through the wall of the envelope at 10 in theusual manner. In order to provide an external contact, a contact cap 11 may be secured to the outside of the glass envelope.

The insulating block 2 is made to fit closely to the walls of the envelope so that the dan ger of a discharge around the electrode structure to the seal will be reduced. In order further to minimize the danger of a discharge striking the seal, a sleeve of glass or other insulating material 12 is placed around the lead-in wire.

I find that the electrode may be ing a packing o life of a tube utilizing this reatly increased by providglass wool 13, which has been treated with an alkali earth bromide, between the rear end of the electrode structure and the seal. Barium bromide is especiallysuitable for this purpose. The glass wool, in a tube wherein the envelop surrounding the electrode structure is in the nei hborhood of three-quarters of an inch 1n iameter, may be treated with about two drops of a solution of one gram of barium bromide in 1000 cos, grain alcohol. In a larger tube more of the solution may be used. During the construction of the tube the glass wool is put in its proper position and saturated with a few drops of alkaline earth bromide, after which the tube is exhausted. A discharge is preferably passed between the electrode during the exhausting operation in the usual manner in order to insure more complete evacuation of the occluded and adsorbed gases. After the tube has been fully evacuated, it is filled with a rare gas, e. g., neon or helium, to any desired pressure, for example, 5 to 15 mm. of mercury.

Fig. 2 shows an electrical discharge tube having two electrode structures therein similar to that shown in Fig. 1.

By constructing the device in the manner set forth and by utilizing the glass wool treated with an alkaline earth bromide, a tube of extremely long life and efficient opcrating characteristics is obtained.

I have determined by tests that the life of the tube may be 12,000 hours or more and that transparency of the tube is not interferred with by formation of a coating of sputtered particles, as occurs in certain types ofdevices known to the prior art;

It will be obvious to those skilled in the art that the invention is capable of a variety of modifications and adaptations and that the present disclosure is intended merely to illustrate its nature without limiting its scope, which is expressed in the following claims.

What is claimed is:

1. An electrical discharge device comprising an envelope, a block of insulating material positioned in one end thereof and substantially filling the opening therein, an electrode mounted centrally of said block and projecting therethrough, a lead-in wire for said electrode sealed through the end of said envelope, and a quantity of glass wool, treated with an alkaline earth bromide, packed between said block and said seal.

2. A device in accordance with claim 1, wherein the envelope is filled with rare gas at a pressure of a few millimeters of mercury, and the electrode is of tantalum.

3. In an electrical discharge device, an envelope containing rare gas at reduced pressure, a pair of electrodes for passing a discharge therethrough, an a quantity of glass wool coated with an alkaline earth bromide positioned adjacent to one of said electrodes.

4. In an electrical discharge device having an envelope containing an atmosphere at re duced pressure, means for lengthening the useful life of the device comprising an insulating material coated with a small quantity of alkaline earth bromide.

5. A device in accordance With claim 3, wherein the coating material is barium bromide.

6. A device in accordance with claim 1, wherein the block of insulating material has a hollow sleeve extension which surrounds and extends beyond the operating point of the electrode.

In testimony whereof, l[ have signed my name to this specification, this 24th day of October, 1929,

ALFRED HENRY STAIGER. 

